A conventional domestic fan typically includes a set of blades or vanes mounted for rotation about an axis, and drive apparatus for rotating the set of blades to generate an air flow. The movement and circulation of the air flow creates a ‘wind chill’ or breeze and, as a result, the user experiences a cooling effect as heat is dissipated through convection and evaporation. Such fans are available in a variety of sizes and shapes. For example, a ceiling fan can be at least 1 m in diameter, and is usually mounted in a suspended manner from the ceiling to provide a downward flow of air to cool a room. On the other hand, desk fans are often around 30 cm in diameter, and are usually free standing and portable.
A disadvantage of this type of arrangement is that the forward flow of air current produced by the rotating blades of the fan is not felt uniformly by the user. This is due to variations across the blade surface or across the outward facing surface of the fan. Uneven or “choppy” air flow can be felt as a series of pulses or blasts of air and can be noisy. A further disadvantage is that the cooling effect created by the fan diminishes with distance from the user and the user may not be situated at the location or distance where it is possible to feel the greatest cooling effect. This means that the fan must be placed in close proximity to the user in order for the user to receive the benefit of the fan.
Other types of fan are described in U.S. Pat. No. 2,488,467, U.S. Pat. No. 2,433,795 and JP 56-167897. The fan of U.S. Pat. No. 2,433,795 has spiral slots in a rotating shroud instead of fan blades. The circulator fan disclosed in U.S. Pat. No. 2,488,467 emits air flow from a series of nozzles and has a large base including a motor and a blower or fan for creating the air flow.
In a domestic environment it is desirable for appliances to be as small and compact as possible due to space restrictions. For example, the base of a fan placed on, or close to, a desk reduces the area available for paperwork, a computer or other office equipment. Often multiple appliances must be located in the same area, close to a power supply point, and in close proximity to other appliances for ease of connection.
The shape and structure of a fan at a desk not only reduces the working area available to a user but can block natural light (or light from artificial sources) from reaching the desk area. A well lit desk area is desirable for close work and for reading. In addition, a well lit area can reduce eye strain and the related health problems that may result from prolonged periods working in reduced light levels.
In addition, it is undesirable for parts of the appliance to project outwardly, both for safety reasons and because such parts can be difficult to clean.